Because it can easily lead to horrible performance? (tree graphs are much easier to manage and optimize than arbitrary graphs)

Because user studies show that node based compositors confuse even the people who use them every day? (honestly, I think the only people who use them effectively are the authors, and the few users who could have authored the software)

You have clearly not used a node-based program. Every serious image editing software for motion (Nuke, Fusion, Flame) offers node-based image editing for one simple reason: it is more powerful and easier to use.

Is the initial learning curve steeper? Yes. But the eventual speed and power is much, much greater.

Horrible performance? You sir, are clearly not acquainted with Photoshop, the de facto standard for horrible performance when it comes to image editing. Try to apply a lens blur to an 8000x10000px file - go ahead. I'll still be here in 4-5 hours when Photoshop finally craps out and runs out of memory. Nuke would do that operation in moments, all the while providing real-time updates of its progress.

And there's more to performance than just CPU cycles: look at this case study.

I apply a blur, do a selection, apply another blur to the selection, do some painting, and then decide I want to change the first blur. Oops. In Photoshop, you have to undo everything up to the point of the change you want to make in order to change something (I realize you're adding adjustment layers, which are an inelegant solution at best, and apply to a very small subset of PS's features).

In a node-based program, every operation you've ever done is always available for adjustment. That's performance. That's productivity.

If you really think that node-based systems confuse even the people who use them every day, you really need to talk to someone who works in VFX. Every single serious VFX program uses nodes, and people do amazing, amazing work with them.

So, your responses to this question are just plain wrong, as I have clearly shown.

This is an issue worthy of immediate implementation (as Photoshop is about 10 years overdue for a complete backend re-write and UI overhaul anyway, you can do it at the same time).

Yes, I have -- I've been using them for over 25 years. And I've read the UI studies, and talked to users, and they all support the conclusion that node based editing is much harder to use. It can be more flexible in some cases (which can also get you into trouble).

I am well acquainted with Photoshop - the standard for high performance on the desktop. The same Photoshop that hardware makers use to stress test their systems because it has higher throughput than almost everything else available.

Just because you don't have the experience does not mean that the people writing the software lack experience.

No, you have not shown that my answers are wrong, just that your experience is limited.

If it's harder to use, why is it used in the most demanding of image-processing fields - VFX? Why is it used in programs for which speed and power are worth paying $150,000, like Flame?

In my experience, NOT using a node-based system gets you into more trouble - when everything is explicitly laid out on the graph, it's easy to see what's happening and how to do what you want. In a layer-based program like PS, it's impossible to get an overview of your image setup, and you have to constantly reverse-engineer the assumptions that went into the program in order to make it do what you want.

And Photoshop isn't the standard for high performance on the desktop - it's just the only horse in the race with a marketing budget. Therefore it's the only app that gets attention in hardware tests. Like I said - try a lens blur on a largish image - PS just crashes. It's slow, hogs RAM like nobody's business, and can't work with large images. Hardly the standard of high performance...

But in any case, I would be interested to see the studies you're talking about - could you link to them?

Why are they only used in high end VFX tools, and not in consumer applications? Um, probably because they're incredibly difficult to use, but flexible, if you take a lot of time to learn to use them correctly.

You can easily see what is happening in Photoshop -- the layers palette is a tree graph, no reverse engineering required. And all but the most trivial node based graphs are much more difficult to decipher (except maybe for the person who created them).

LOL. You really are stretching your credibility, especially by harping on a single filter. Photoshop uses as much RAM as it needs for your image and the operations you tell it to do. And most Photoshop operations run at the limit of your RAM's speed (and some at your GPU's speed).

Can you not see that your rants here are working against your goal of getting node based editing in Photoshop? You would have been far better off just asking and pointing out why you like node based editing.

Chris, I simply don't get you. Isn't it your JOB to listen to customers and improve PS? Charle has given you real world facts and your simply ignoring them, at the expense of your own product. Shame. BTW I work in the VFX industry. The reason i found this thread is because it was being passed around at work. It was a source of laughter someone involved in the development of PS couldn't understand the obvious advantage of node based workflows. You continue to amuse us.

You're not explaining errors and mistakes, you're trying to whitewash areas where PS could be improved or is weak.

I realize you've been working for Adobe for 16 years, and therefore have a serious vested interest in it and the status quo, and are also probably not too in tune with the current state of affairs out here in the real world. That's cool, and I'm willing to cut you some slack on that front.

But your complete inability to see any room for improvement on this front is frankly baffling for someone working on a feedback forum.

Serious companies like The Foundry making serious software like Nuke think that scanlines and nodes are the way to go. My experience - and the experience of thousands upon thousands of others - are that they're on the right track.

For you to just categorically discount all of that as "errors and mistakes" is - well - an error and a mistake. You can't just discount all of this stuff out of hand and claim to be doing your job (or at least not well, or I deeply misunderstand what you're doing here on this forum...).

Charles - before casting stones, you really should read your own posts. You attacked the developers and users of Photoshop from the start. And you made a lot of claims that really cannot be justified based on real world experience (but might seem right based on limited experience in one isolated industry).

You are entitled to your opinion that Nuke is a great UI. Please understand that your opinion is not shared by everyone (in fact, most would vehemently disagree with you).

You could have simply added your request here, and listed the reasons why you thought a node based UI was a good idea. That might have helped the case. Instead you continue to belittle developers and users with far more experience than yourself. Instead you chose to post "facts" which are not based on reality, but based on your own limited experience. And every time you chose to attack another facet of Photoshop, your exposed even more of your own inexperience.

I never said there was no room for improvement in Photoshop - just that node based UIs are not an improvement, but a huge step backward in usability and performance. In some cases a Node based display might be a good idea to help people visualize more complex layer structures. But arbitrary graphs do not help understanding, and cause not only confusion for the user, but arbitrarily poor performance in applying the graph.

Just because you learned one niche application with a particular UI does not mean that UI is a good idea for everyone else. Nor does it mean that the UI is without major problems -- just that you are comfortable with that particular UI and don't understand more straightforward UIs. (and may not fully understand the UI you are using if you do not know it's shortcomings)

Your current claim is akin to something I heard (jokingly) from a British user: "I learned to drive on the left with a clutch, thus it must be superior and everyone else should be driving on the left with a clutch."

Limited experience and comfort with a particular approach does not make it better. And please understand that some people might have (long) experience using a variety of UIs and have spent some time studying the strengths and weaknesses of the various approaches. When those people try to explain that your limited experience is clouding your judgement - you might want to listen.

Chris, can you please provide links or references to the user studies you refer to? Also, are you attributing horrible performance to both tree graphs and arbitrary graphs, or just tree graphs, or just arbitrary graphs? Also, can you please define your use of the word "effectively"?

Chris,
Its jaw dropping to see such a ridiculous opinion coming from a Photoshop employee!
Node based workflows (not only in compositing but also in 3d) are constantly used "effectively" in the VFX industry.
More and more software is try to become node based. In fact, this way of working is quickly becoming a standard.
Photoshops workflow is behind the times (and if your opinion is anything to go by) it doesn't look like it will catch up any time soon!

As an artist in the games industry I have to say that a Node based system would be a dream come true, working with Photoshop at the moment isn't a particularly trying process I must admit, there isn't much for me to complain about. However, node based systems can be extremely useful when attempting to work with something non-destructively, which is important in my line of work. I have to say that it's probably not something a great deal of people will find a use for, it's one of those things that a majority of people will simply glance over; you're hardly going to need a node based system to crop family photos or when doing digital paintings. However if you're working on textures it would be a very useful feature.

For example, using a node system for adjustments and filters on individual layers or groups would be useful, admittedly adjustment layers already exist essentially allowing you to do this already, however for filters there is no such option, why isn't there a real time sharpening layer? Or, if it were node based, you could simply plug a node into a layer or group that sharpens them, and in no time you have a completely non-destructive workflow which would aid in the iteration process.

Just my thoughts, a node based system would be a nice addition to Photoshop but by all means shouldn't replace the tree system that already exists, but rather run in parallel.

Sharpening is an area operation, which cannot be done as a "filter layer" without serious performance problems on larger images (we tried anyway, and it was worse than expected). Adding more area operations would make things much, much worse (somewhere between geometrically and exponentially worse).

Node based editing does not change the math - just the UI. You might get a proxy result quickly in some cases, but that doesn't prevent you from getting the same horrible performance you'd get from layer based editing.

Smart filters don't do what node-based editing does, and they don't offer the same control. I've used them, they don't. One of the huge benefits of node-based control is the way everything can connect to everything else - you can re-use nodes and layers in complex ways that are labour-intensive or simply impossible in a layer-based program. They're admittedly an improvement over the way PS used to work, but they are nowhere near the power and flexibility that is possible.

Sharpening, blurring, and - in fact - every single operation can be done as a "filter layer" in programs like Nuke. It works fine, so it seems that it can be done (even if your engineers don't know how to do it). And Photoshop can't handle large images in any case, so I don't see how performance on large images is an issue (like I said, try to do a lens blur on an 8000x10000px image - not a ridiculous size by any means. I just tried this on Mac OS 10.6 with 8GB of RAM, and it wouldn't complete due to out-of-memory).

And you're right - I'm conflating two things here, and for that I apologize. Programs like Nuke use scanline-based rendering which handle large images way, way better than Photoshop does (I have opened single-layer images in the dozens of gigabyte range, something Photoshop chokes on) and support Areas of Interest and Proxy quality (to easily preview processor-intensive effects over either a small area, or at lower quality). Because node-based apps typically work this way, I tend to associate the two things, but you're right - they're not the same.

Connecting to everything is also one of the greatest weaknesses of node based editors - because you can construct graphs of arbitrary complexity (and cycles).

Photoshop can easily handle images up to 300,000 pixels by 300,000 pixels. (though most people don't have the RAM to make those work quickly) And we'd like to go larger - but current disk systems are kind of slow at moving terabytes of data.
Not all plugins will work on images that large, because different plugins have different buffer requirements (and something like Lens Blur has some complex requirements).

Photoshop does not choke on large images, but your system may not have the RAM or disk speed to handle those large images.

Nuke's scanline approach is quite a bit slower than a tile based approach for image processing unless you are doing simple 1:1 color adjustments or fills.

Yes, Nuke does offer "filter layer" like nodes - just not very quickly, and the complexity grows unreasonable very quickly as I already stated.

Re-editability was a specific use case, not a stated primary goal. There are many advantages of node-based systems, and they implement this better than smart filters or adjustment layers.

Flexibility is not a weakness, it is a strength.

Well, I beg to differ on the choking issue. If one app can perform a function on a certain image on a certain system, and another one can't, I would say the second app has choked. Not being able to execute a function - or executing it absurdly slowly - is choking in my book. Maybe you have a different definition.

It's all well and good if things are dandy on a system with an SSD raid and 64GB of RAM, but the rest of us live in the real world.

Your theories about why node-based apps don't work sound fine in principle, but the fact is that in the real world, they work better - plain and simple.

I mean, if you're talking about making bad graphs, what's stopping me from using 400 smart filters on one layer? You can never protect the users from themselves.

In the real world, it's harder to get work done with PS than with a node-based program, because the interface makes no g*d*ed sense, and effects are sprinkled liberally through 20 different tool palettes, menus, and submenus.

And as I said, in real world experience, often PS's performance is so bad as to be literally 0 - no performance at all. I have never had Nuke not do what I needed it to.

In the real world, more people (by far) are using Photoshop for VFX and compositing precisely because it is easier to use and understand.

You are confusing your lack of experience with ease of use. Just because you do not understand Photoshop's layer model does not mean that millions of other people have that same lack of understanding. To most people, Photoshop's UI makes quite a bit of sense, and Nuke's makes very little sense (especially with actual production graphs).

How many teenagers buy or pirate a copy of Nuke and start compositing immediately? How many do that with Photoshop? A rough estimate would put Photoshop ahead by at least 5 orders of magnitude. Why? Because Photoshop is easier to use and understand.

Nuke is useful for many things, but it is simply not designed for mainstream imaging, approachability, ease of learning, or ease of use.

And, again, something is wrong if you're seeing serious performance problems with Photoshop. Normally Photoshop is the benchmark for system performance because it is so highly optimized and stresses systems harder than most other applications.

Well, for matte painting, sure, but not VFX or compositing as I understand it. It's part of the process, but for its paint tools, not its comp tools.

I am actually quite experienced with PS. Its just not logically laid out.

To most people, PS is all the know. It's the industry leader through monopoly, not excellence. People don't use Nuke because it doesn't have the paint tools (which is one of the main selling points of PS), it doesn't have the marketing, and it doesn't have all the whiz-bang gadgets built-in. Also, it's specifically for motion work, while PS is specifically for still work (which is what 98% of people are looking for).

There's a lot of reasons why PS is in a dominant market position, but UI excellence is not one of them.

People like the UI because they know nothing else, not because it's the best way, or even the best possible implementation of the way it uses.

And, again - PS is the benchmark for system performance because of its monopoly status, and no other. Nobody cares how CorelPaint does on this chip or that, because nobody uses CorelPaint. Same with the GIMP.

PS's monopoly position has made the team complacent and highly resistant to much-needed change.

Photoshop is used quite often for VFX and compositing. Much of the time it is used because it is easier and faster to use than more expensive niche products.

Photoshop has been used for movie work since 1988 (that's one of the reasons it exists - ask John Knoll).

Photoshop may not seem logical to you - but it seems far more logical to most users than Nuke.

You like Nuke's UI, because you are comfortable with it. That does not make it a great UI, just the one that you are most comfortable with.

Photoshop is a benchmark for performance because of it's high performance, as well as it's widespread usage. And that certainly doesn't come from our nearly non-existent marketing (honestly, Nuke probably has a larger marketing budget than we do).

Your inexperience is still clouding your judgement, and you are making more exaggerated claims without any basis in fact.